The invention relates to a glow plug arrangement for an air charged injection combustion engine.
French Patent (FR-PS) No. 76 30 914 discloses a glow plug for the vaporization and ignition of fluid fuel. The glow plug is provided with a cylindrical, smooth heating rod part which is disposed in the injection region of two fuel streams of an injection nozzle arranged at right angles to the heating rod. Glow plugs of this kind are not suitable to fulfill the efficient intensive atomization and disturbance free ignition of the fuel.
The invention is based upon the problem to achieve improved fuel conditioning and ignition by providing a glow plug arrangement requiring a small construction space and of simplified construction.
The solution of this problem is inventably obtained by providing that the heating rod is disposed at a sharp angle to the injected fuel stream and is provided in the region impinged on by the fuel stream with an irregular surface to improve the atomization and ignition of the fuel, said irregular surface being formed as a plurality of ring grooves around the circumference of the heating rod.
In German published application (DE OS) No. 26 40 314 a glow plug is disclosed with an uneven surface at the free end of the heating rod part. However, in this arrangement the thread formed indentations at the rod part serve as a guide for a resistance heater wire. Because of the rounded outer surface of the heating rod in this arrangement, no splitting up of the fuel into the smallest drops is achieved.
Through the inventive measures, namely to provide the heating rod of the glow plug with sharp edged outer surface parts in the region of the compact impinging fuel stream, the injected fuel from the injection nozzle is so split up that the fuel is divided into many small droplets. Therewith a large fuel outer surface area results which is associated with a good gas mixture with the air to form a readily combustible gas mixture.
Further objects, features, and advantages of the present invention will become more apparent from the following description when taken with the accompanying drawing which shows, for purposes of illustration only, an embodiment in accordance with the present invention.